AP BIOLOGY

Detailed explanation-1: -The two “sister” chromatids are joined at a constricted region of the chromosome called the centromere. During cell division, spindle fibers attach to the centromere and pull each of the sister chromatids to opposite sides of the cell.

Detailed explanation-2: -A sister chromatid refers to the identical copies (chromatids) formed by the DNA replication of a chromosome, with both copies joined together by a common centromere. In other words, a sister chromatid may also be said to be ‘one-half’ of the duplicated chromosome. A pair of sister chromatids is called a dyad.

Detailed explanation-3: -Centromere The centromere appears as a constricted region of a chromosome and plays a key role in helping the cell divide up its DNA during division (mitosis and meiosis). Specifically, it is the region where the cell’s spindle fibers attach.

Detailed explanation-4: -Centromere is a primary constriction present on the chromosome where the chromatids are held together.

Detailed explanation-5: -Scientists now appreciate that the centromere is a region of specialized chromatin found within each constricted chromosome that provides the foundation for kinetochore assembly and serves as a site for sister chromatid attachment (Figure 1).